Dev encircled odd members in the following plant groups based on their type but made one mistake. Find the group with mistake.
A Neem, Mango, 
, Coconut
B Groundnut, 
, Mustard, Rice
C Rose, Hibiscus, 
, Watermelon
D Coriander, Spinach, 
, Mint
why A is not correct answer here. Mustard is herb and and others are trees.